Steam boiler



May G 1924. ,1,493,273

A. D. PRATT STEAM BOILER Filed Nov B 1920 INVENTOR BY f @aeg ATTORNEYS Patented May e, lees.l

ARTHUR nrnerr; or suona* HILLS, NEW JEnsnY, AssIGNon.- To una Bassoon a wILcox COMPANY, on rayonne, Naw Jirnsum a CORPORATION or NEW JERSEY.

STEAE- BOIIER.

applicativa and :sweater e, 1920. serieu no. 422,513. f-

To aZZfwhofm, 'it may iconcern.-

Be it `known that I, `ARTHUR Stirling type, and will be understood byv reference to the accompanying drawin s 1n which the igure is avertical, longitu inal section of one embodiment thereof, the furnace of the boiler being shown broken away.4

Referring to the figure, the boiler shown com rises'ftransverse, upper steam and water rums 1, 2 and 3, and a mud drum 4, the

' upper drums being connected to the mud `drum by means of banks of tubes 5, 6 4and 7. may use. a single mud drum 4, as

shown, or aseries of connected mud drums, andI intend to, cover both structures" by,

the words lower chamber in the claims. The three upper steam and waterv drums must, howeverfbe connected to this lower "chamber, whether in the form of one drum or several connected-drums. The steam l space of the center drum2 is interconnected with the front 'and rear drums by curved steam-circulating Vtubes 8 and 9. The water spaces of the front and middle drums are connected by water circulating tubesv 10, the upper row ofwhich tubes support til- -ing 11. In the form illustrated, no wate circulators are provided between the middle and rear steam and water drums.

A bailie 12 is supported' on the tubes 'of the front bank and .extends upwardly from the mud drum 4 to the u per end of the bank. The middle bank o tubes 6 is provided with a baile 13 extending from the middle drum 2 downward toward the mud drum`4.4 Cross ba-iiles Maand 15 are pro- .videdat the rear ofthe rear bank 7. A

superheater 16 ofthe'usual construction is shown inthe second pass of the boiler. v

The gases from the furnace follow the Vdirection indicated by the arrows, ow upward along the tubes of the bank 5i and` downward through the second pass, and upward along the tubes of 'the bank 7 and out of the gas outlet 17.

In the form illustrated, the middle and rear steam and water drums are on substan- D. lua'rr,V a citizen of the United States, residing at.

- rating.

tially thefsame level, which vis higher thanthe level of the front steam and water drum.4 The main steam outlet y18 is, connected to the rear steam and water drum in, the form against the buttpstra s ci the middle and rear drums, I'prov e a special baille 21 which extends from the baille 13 to the drum 3 below the butt straps 20,and as a means for supporting and protecting such bams I utilize water tubes extending from the middle bank to the rear drum, so that such portion of these tubes on which the baille 21 rests will be approximately horizontal. While these tubes may form a art of either the rear or middle bank of tu es,

in the form illustrated, I have utilized the' front row 22 ofthe' tubesA ofthe rear bank which, as shown` in the'd-raw'ings, have been separated from the remainingl tubes of such bank until the lower-portion thereof is sub:`

stantially parallel with the tubes of the 4 middle bank, but in the rear of the baille 13. The upper portions of the tubes 22 are curved and Aextend rearwardly ffand connect into the rear jdrum 3.

With the tubes and bal'lles thus arranged, the gases passing upward .in the rear pass cannot impinge a gunst-the butt straps 20, on any considera le portion o the rear steam and water drum which may be with out water when the boiler is operated at high ln the forml illustrated, the special baille 21 cooperates with the 'upper rportions of the vertical baille 13 to close the space between the upper rear-and middle drums, to 'i may extend entirely across the space between these two drums and contact directly with each of them, such special baiile being supported on the horizontal-"portions of the tubes 22. y Jf 1. A steam boiler of the class describedl comprising'three upper, transverse connected by banks of tubes to v a lower' connected water chamber, a baie extending downward from the middle upper drum et the rear of the benk connected to ythat drum, Some of the tubes connected to the rear upper drum beingv directed at their upper portions toward said baffle, and e protecting ae supported on said upper portions and extending from the rear upper drum to said baiiie to protect the rear upper drum from excessive heating.

2. A steam boiler of the class described comprising three' upper, transverse drums bybanks of tubes to a lower 'water chamber, the water spaces of the two rearmost drums vbeing unconnected except through the Water chamber, battling to direct the gases along said lbanks *with e down-pass in the middle bank and ven uppassin the rear bank, the upper portions of thek front row of the rear benk .of tubes being directed toward the middle benk of tubes, and baiing to divert the gases from the space between the two reermost drums, some of said lest-named baflling being supported on-said upper portions and the remeinder extending along the rear of the middle bank.

3. A steam boiler of the class described 'comprising three upper, transverse drums 

